| 场地类别分类方案研究 |
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| 引用本文： | 陈国兴,丁杰发,方怡,彭艳菊,李小军.场地类别分类方案研究[J].岩土力学,2020,41(11):3509-3522. |
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| 作者姓名： | 陈国兴 丁杰发 方怡 彭艳菊 李小军 |
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| 作者单位： | 1. 南京工业大学 岩土工程研究所，江苏 南京 210009；2. 江苏省土木工程防震技术研究中心，江苏 南京 210009；
3. 中国地震局地壳应力研究所，北京 100085；4. 北京工业大学 建筑工程学院，北京 100124 |
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| 基金项目： | 国家重点研发计划项目（No. 2018YFC1504301）；中国地震局地壳应力研究所中央级公益性科研院所基本科研业务专项项目（No. ZDJ2017-28）. |
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| 摘 要： | 基于性能的抗震设计，要求工程师设计出具有预期抗震性能的结构，一个关键因素是地震作用的确定，这在很大程度上取决于局部场地条件。通过收集和分析北京、苏州和唐山城区956个钻孔资料，建立地表20 m和30 m深土层走时平均剪切波速VS20和VS30的关系式；现场钻探获取北京城区深105 m的典型钻孔原状土样，试验给出各类土体动剪切模量和阻尼比曲线；建立北京城区170个钻孔的场地反应计算模型，采用Nakamura提出的HVSR法和陈国兴等提出的弱震法估算场地基本周期TS值，结合国内外现行抗震规范的场地分类及一些学者对场地分类的研究成果，提出两种新的场地分类建议方案：基于等效剪切波速VSE和覆盖土层厚度H（地表至剪切波速VS ≥ 500 m/s的基岩深度）的双指标场地分类方案及基于VSE、H和TS的三指标场地分类方案。提出的场地分类方案对我国现行抗震规范场地分类方法的改进有参考价值。
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| 关 键 词： | 地震场地效应 场地类别 覆盖土层厚度 走时平均剪切波速 场地基本周期 |
| 收稿时间： | 2020-02-09 |
| 修稿时间： | 2020-04-13 |
Investigation of seismic site classification scheme |
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| CHEN Guo-xing,DING Jie-fa,FANG Yi,PENG Yan-ju,LI Xiao-jun.Investigation of seismic site classification scheme[J].Rock and Soil Mechanics,2020,41(11):3509-3522. |
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| Authors: | CHEN Guo-xing DING Jie-fa FANG Yi PENG Yan-ju LI Xiao-jun |
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| Institution: | 1. Institute of Geotechnical Engineering, Nanjing Tech University, Nanjing, Jiangsu 210009, China;
2. Civil Engineering and Earthquake Disaster Prevention Center of Jiangsu Province, Nanjing, Jiangsu 210009, China;
3. Institute of Crustal Dynamics, China Earthquake Administration, Beijing 100085, China;
4. College of Architecture and Civil Engineering, Beijing University of Technology, Beijing 100124, China |
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| Abstract: | The performance-based seismic design requires engineers to design structures with desired seismic performance for a specific level of earthquake ground motions. One of the key factors is the determination of seismic effect, which depends on the local site condition. This paper collected 956 borehole profiles and shear-wave velocity profiles of soil lithology in Beijing, Suzhou and Tangshan urban areas, China. The correlations of the time-averaged shear-wave velocities VS20 and VS30 for the corresponding top 20 m and 30 m depths for sites are established. Cyclic triaxial tests were performed on typical samples of undisturbed soils at the depth of 105 m taken from Beijing urban area in this study, and the shear modulus reduction and damping increasing curves with increasing shear strain for various types of soils are given. Nonlinear site responses of soil column models for 170 borehole profiles in Beijing urban area were computed, and the site fundamental periods TS for each soil column model were estimated through the Nakamura’s HVSR method and the Chen’s weak-motion method. Subsequently, combined with the site classifications of the current seismic design codes at home and abroad and the recent research results of some scholars on site classification, two alternative seismic site classification schemes were proposed, namely the two-proxy method based on the H (soil depth from the surface to bedrock with shear-wave velocity ≥ 500 m/s) and VSE (time-averaged shear-wave velocity for the smaller value of both the upper 30 m and H), as well as the three-proxy method based on the H, VSE and TS. The two proposed site classification schemes in this study provide a beneficial reference to modify the site classification in the current seismic codes in China. |
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| Keywords: | seismic site effect site classification soil depth from the surface to seismic bedrock travel time averaged shear wave-velocity site fundamental period |
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